What led to the War in Ukraine?

On February 24, Russian president Vladimir Putin announced the launch of a “special military operation” in Ukraine.

 

On February 24, Russian president Vladimir Putin announced the launch of a “special military operation” in Ukraine. Putin claimed that the leaders of the breakaway republics of Donetsk and Luhansk in the Donbass region had asked for military assistance against Ukrainian aggression. But the current military operations have spread much beyond the Donbass region. What brought about this situation?